shell/caucase.sh: Improve built-in test suite.

Simplify code a bit.
Change directory when starting caucased, so all files are stored inside
test's temporary directory (and not just the database).
Tolerate caucased not immediately starting.
Fix CA presence tests (well this is embarrassing).
List test directory content when failing, as it will get deleted shortly
after.

shell/caucase.sh

@@ -1115,6 +1115,7 @@ EOF
   _test() {
     # shellcheck disable=SC2039
     local netloc="$1" \
+      status \
       tmp_dir \
       caucased_dir \
       caucased_pid
@@ -1127,30 +1128,55 @@ EOF
     fi
     tmp_dir="$(mktemp -d --suffix=caucase_sh)"
     caucased_dir="$tmp_dir/caucased"
-    caucased --db "$caucased_dir/db.sqlite" --netloc "$netloc" &
+    mkdir "$caucased_dir"
+    if cd "$caucased_dir"; then
+      :
+    else
+      echo 'Could not setup caucased directory'
+      return 1
+    fi
+    caucased --netloc "$netloc" &
     caucased_pid="$!"
     # shellcheck disable=SC2064
     trap "kill \"$caucased_pid\"; wait; rm -rf \"$tmp_dir\"" EXIT
+    # wait for up to about 10 seconds for caucased to start listening (initial
+    # certificate generation.
+    for _ in $(seq 100); do
+      CURL "http://$netloc" > /dev/null
+      status=$?
+      test $status -eq 0 && break
+      # curl status 7 means "cnould not connect"
+      if [ $status -ne 7 ]; then
+        echo "curl failed while accessing test caucased with status $status"
+        return 1
+      fi
+      sleep 0.1
+    done
+    if [ $status -ne 0 ]; then
+      echo 'Timeout while waiting for caucased to start'
+      return 1
+    fi
     if cd "$tmp_dir"; then
       :
     else
-      echo 'Could not setup temporary directory'
+      echo 'Could not enter test temporary directory'
+      return 1
     fi
     _main --ca-url "http://$netloc" --update-user
-    if [ -r cas.crt.pem ]; then
+    if [ ! -r cas.crt.pem ]; then
       echo 'cas.crt.pem not created'
+      find . -ls
       return 1
     fi
-    if [ -r cau.crt.pem ]; then
+    if [ ! -r cau.crt.pem ]; then
       echo 'cau.crt.pem not created'
+      find . -ls
       return 1
     fi
   }
   if [ "$#" -gt 0 ] && [ "x$1" = 'x--test' ]; then
-    if [ "$#" -eq 1 ]; then
-      _test "localhost:8000"
-    elif [ "$#" -eq 2 ]; then
-      _test "$2"
+    if [ "$#" -le 2 ]; then
+      _test "${2:-localhost:8000}"
     else
       echo 'Usage: --test [<hostname/address>:<port>]'
       return 1